Rare but important entity: perineal endometriosis

Surgically treated 130 cases of perineal endometriosis with a suggested "nomogram"

Key Points

Highlights:

• Perineal endometriosis is a rare, albeit very important type of endometriosis accounting for at most 0.37% of women consulting for treatment of endometriosis.
• Both the diagnosis and therapy of perineal endometriosis are cumbersome, due to the rarity and low awareness of this particular entity.

Importance:

• In a comprehensive review of perineal endometriosis, around 300 cases were found until 2021.
• Invasive growth of perineal endometriotic lesions may reach the anal sphincter, vaginal wall, or rectum.

What's done here:

• The authors retrospectively analyzed a series of 130 perineal endometriosis patients who were operated on in Peking Union Medical College Hospital over 3 decades.
• Surgery is the primary treatment for perineal endometriosis; and, multiple lesions and anal sphincter involvement are independent risk factors for recurrence.
• Wide resection with negative margins should be preferred.
• The proposed nomogram by the authors had an effective prognostic prediction for these patients receiving surgical excision.

Limitations of this study:

• Postoperative follow-ups were done via outpatient visits and telephone inquiries which might have resulted in bias about the exact time of recurrence.
• Only 37.5% (5/16) of patients with recurrence of symptoms had histopathologic confirmation.
• Non-responding postoperative follow-up requests are around 20% and this rate may cause vagueness in the research results.
• In addition, due to the small number of cases, the effectiveness of this nomogram was achieved through internal verification.

Lay Summary

Dr. Zhu and colleagues from Peking Union Medical College Hospital have published their retrospective research on "surgically treated perineal endometriosis cases" in a recent issue of BMC’s Women’s Health.

Perineal endometriosis is a rare type of endometriosis accounting for at most 0.37% of women consulting for treatment of endometriosis. A literature search starting from 1923 for perineal endometriosis revealed around three hundred cases till 2021. Diagnosis and therapy could be problematic mainly due to its rarity and low awareness of this kind of endometriosis among clinicians. Though rare, perineal endometriosis is very important clinically since it could be debilitating due to the infiltration to nearby anatomical compartments such as the anal sphincter, vaginal wall, or rectum.

The authors retrospectively analyzed 130 perineal endometriosis patients that were surgically treated in Peking Union Medical College Hospital over three decades in order to summarize the clinical features and treatment of this rare entity. The authors have both presented the clinical information of perineal endometriosis cases and a prognostic nomogram for the first time.

Almost 45 thousand patients received surgical treatment for endometriosis between 1992 and 2020 at Peking Union Medical College Hospital, only 130 had surgery for perineal endometriosis with 104 complete follow-ups and analyzed for the prognostic outcome. All received local surgical excision with 0.3–0.5  cm of negative margins except one due to wide involvement of the anal sphincter and rectum.

Three factors of the multivariate Cox regression model were included in the prognostic nomogram, and the nomograms for 36, 60, and 120 months without recurrence were established. The independent risk factors significant in statistical analysis were “multiple lesions” and “anal sphincter involvement”. This proposed nomogram yields better discrimination with statistical significance and gives a useful tool for prognostification. 

However, this retrospective study is not without some limitations. First, postoperative follow-ups done during outpatient visits and phone calls could result in recall bias about the exact recurrence time; only one-third of patients with recurring symptoms had microscopic confirmation which surely may produce more convincing data. Also, non-responding patients during postoperative follow-up may cause weakness in the final results of this study. Besides, due to the apparently small number of patients, the effectiveness of this nomogram was achieved through internal verification.

Research Source: https://pubmed.ncbi.nlm.nih.gov/36435830/